Contemporary machining involves rotating a cutting tool to remove material from a work piece. One readily known configuration involves using a cutting tool mounted on a rotatable arbor of a machining system. The arbor and cutting tool are keyed such that rotation of the arbor results in a like rotation of the cutting tool. The cutting tool is brought into cutting engagement with the workpiece which is itself mounted in a fixture. Examples of such machining systems are mills, lathes, gear cutting machines such as gear hobbing machines, etc.
It is often times necessary to axially locate the cutting along the length of the arbor to ensure that the cutting tool is at the desired axial location along the arbor for cutting. Further, it is not uncommon to utilize several cutting tools on a single arbor. As one example, a first cutting tool may be used for a rough cut, while a second cutting tool may be used for a finishing cut. In this case, each of the cutting tools must be axially located along the arbor in a known location so that the cutting operation may be achieved.
Axially locating the cutting tool on the arbor is typically done via spacers. One or more of these spacers may be situated on one or both sides of the cutting tool to locate the same in the appropriate axial position along the arbor. However, it has been found by the Applicant herein that after installing the cutting tools and the spacers on the arbor, a deflection in the arbor occurs, causing the cutting tool to deviate from its desired location. This deviation is referred to as “run out” and can lead to undesirable imprecision in machining. While there are generally several mechanisms which contribute to such run out, generally, the same occurs due to the tension placed on the arbor. Indeed, the arbor includes a nut at one end thereof which is tightened after installing the cutting tools and spacers thereon. This tightening places the arbor in tension, while at the same time compressing the spacers and cutting tool against one another. This leads to a deflection in the arbor, and consequently a deflection affecting the theoretical location of the cutting tool.
Unfortunately, the known means for dealing with run out is highly inefficient. One methodology is to run an indicator on one or more axial faces of the cutting tool as it rotates with the arbor to identify which direction the arbor is deflected. Thereafter, an operator will stop the rotation of the arbor, and use a hammer and chisel type tool to attempt to force the arbor back into its desired non-deflected state. This is an extremely time intensive process as it requires repeated iterations of using the indicator to identify where there is a deviation in the position of the cutting tool, then stopping the machine, then hammering, then repeating. Such a process significantly slows down production and leads to highly undesirable set up times.
As such, there is a need in the art for a spacer, a machining system utilizing such a spacer, and related methods which overcome these shortcomings described above. The invention provides as much. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.